Laser radar systems require precise focus mechanisms in order to provide the measurement accuracy demanded in many manufacturing applications. In one laser radar system, a probe laser beam is focused on a target by translation of a corner cube. While a corner cube tends to reduce errors associated with various tips and tilts, conventional translation mechanisms often lack the desired accuracy and stability because the focus stage is large and is situated a significant distance from beam-forming optical components such as focusing lenses. Linear guides can be used, but alignment is difficult and stability over a wide temperature range can be problematic.